Offshore towers for supporting drilling and production platforms are now being erected in water depths over 1000 feet. Costs of constructing and erecting such towers is quite high, sometimes reaching $300 million or more for depths of over 1000 feet. For such high costs, it is mandatory that a tower installed in such water depths be sufficiently rugged in construction to withstand the various forces exerted on the tower once it is erected. Such forces include wind forces, wave forces, forces due to water currents and compression forces due to the weight of the facilities on the top of the tower.
Conventional bottom founded platforms have been constructed in a manner to counteract these forces in a satisfactory manner; however, their cost increases exponentially in water depths over 1000 feet. Because of this, a need exists for an improved offshore tower which can withstand such forces as those mentioned above so that drilling and production operations can continue in an uninterrupted manner in deep water, such as in water depths in the range of 1500 to 2500 feet. The need for improvements in towers of this type further includes the desirability of reducing the cost of deep-water drilling and production platforms while not compromising platform safety or without departing from conventional offshore operating procedures. The present invention satisfies the aforesaid needs.